It is known in the art relating to photographic processing to dry a photosensitive material following a wet chemical process such as developing. At present, the drying of photosensitive materials is most commonly accomplished by surrounding the wet photosensitive material with heated air. Other less common drying techniques include radiant heating, microwave drying heating, and combinations thereof.
Drying time is dependent on the method of drying used and the intensity of the application of the method. The application, for example, of super heated air, can damage the photosensitive material. This damage is evidenced in emulsion stress cracking, uneven gloss, excessive photosensitive material blistering, and burned spots on emulsions.
Alternatively the application of low heat or no heat and low or no circulation air can also have damaging effects on the photosensitive material. This is evidenced by a soft tacky emulsion which lends the photographic material to being easily scratched or damaged; processor transport jams due to the tacky, sticky undried emulsion; gloss variation; and prints and films sticking to one another.
The recurring problem with drying photosensitive materials is the inability to determine when the photosensitive material is properly dry. The need exists to predict or actually know when the drying technology application will produce the desired end effect, i.e. dryness of the photosensitive material. Conventional drying technology requires the constant monitoring of the dryer temperature to accommodate ambient operational site conditions such as relative humidity, temperature, and type of material being dried.
Current methods of dryer control require the measuring of ambient conditions and the measuring of drying chamber conditions and using the measurements to calibrate the drying apparatus. These methods have an unacceptable margin of error and require sophisticated RH instruments that require frequent calibration. The only time-proven test for drying in practice has been to increase drying application intensity to the point where two dried emulsions pressed face to face will not stick to or damage each other. Frequent visual examination is required and the dryer must be subsequently adjusted to assure the correct drying effects are obtained.